Stereo headphone assemblies vary widely in their frequency response, comfort to a listener, and aesthetic design. In some examples, a stereo headphone is configured for high fidelity sound reproduction, that is, for faithfully and accurately reproducing sound information over all or a substantial part of the acoustic audio spectrum.
In some examples of stereo headphones, single loudspeaker drivers are used in each of two earcup assemblies. Such single-driver designs are often inadequate to discerning listeners due to compromises in either a low frequency response or a high frequency response of the selected driver design. In some examples, multiple drivers are used in each of two earcup assemblies, such as with a crossover filter to route different frequency signals to different drivers. Such multiple-driver headphone assemblies are typically bulky, heavy, and difficult to manufacture. Furthermore, they can suffer from undesirable distortion or phasing when multiple drivers feed a common, closed airspace adjacent to a listener's ear.
Alignment characteristics of magnetic fields have been used to achieve precise movement and positioning of objects, such as in linear actuators, linear and rotation stages, goniometers, and mirror mounts. Magnets with precisely aligned fields or regions are used in packaging machinery, and positioning of valve pilot stages for fluid control systems. They are also used in various commercial products including floppy disk drives, flatbed scanners, printers, plotters and the like. In an example, a magnet, such as a manufactured magnet with programmed, precisely aligned polarity regions, can be used in a magnet and moving coil assembly, such as for a loudspeaker.